Been trying to figure out stability problems ( boat leans and plows to left), adjusted trim tab, raise lowered motor, installed foil. I finally took rough measurements to see if motor was centered on boat. It looks like the motor is 1-14" inch left of center and the left transom bolts are 1/4 inch off level(lower than right bolts). Do the factorys (in 1991 anyway) make sure the motor is centered on boat? Its a 1991 procraft 170. 115 mercury outboard.